31C-046, 38A-104 2012-08b-official-interpretation-sprinklers-13r-approved-
BBRS Official Interpretation No. 2012_08b
Date: January 8, 2013
Subject: 8th Edition 780 CMR, Requirements for the use of NFPA 13R.
Background/Discussion:
Requirements for sprinklers in R-Use building is found in:
• Table 903.2 of which note “a” contains the sprinkler requirements for R-Use and mandates NFPA 13
systems in some cases and 13D systems in other cases, but makes no specific mention of 13R systems.
This interpretation is intended to clarify code requirements for when a NFPA 13 R sprinkler system may be
used in R-Use buildings.
QUESTION 1
Table 903.2 explicitly speaks to NFPA 13 and 13D systems but is an NFPA 13R system allowed in certain
cases for an R-Use?
ANSWER 1
Yes, the code does recognize, by default, the use of NFPA 13R systems for R-Use with an aggregate area1 less
than 12,000 sq. ft. and the building is 4 stories or less in height. An R-Use of 12,000 sq. ft. or greater requires a
NFPA 13 system. Also, per note “a” of Table 903.2 a NFPA 13D system may be used for buildings of entire R-
Use, other than R-1 Occupancies and R-2 Dormitories, having no more than three dwelling units and also less
than 12,000 aggregate sq. ft.
1. For the purposes of section 903.2, the aggregate building area shall be the combined area of all stories of the
building and fire walls shall not be considered to create separate buildings.